True, the Mercedes transmission can handle much more torque than the 4.0 S/C engine can produce, but it can't necessarily survive shock loads from being shifted into gear past some arbitrary rpm. In this case, Jaguar picked 3000 rpm.

 

Well, the N/A car has the same issue then.
It could theoretically be revved over 6800rpm
and put into gear. But surely the ZF is no
more suited to this abuse than the 722.6
MB unit?

 

So is the argument that sweet sounding revs would hurt the motor mounts?

Aside from the stupid neutral drop, of course...

 

There is body roll already under 3000rpm in neutral, atleast on my XJR. I can only imagine what it would be if you could rev it higher. Never heard that revving in neutral is bad for the car though... and I bet the engine mounts are loaded way harder when flooring it in 1st.

 

Very often the manufacturer's safety tolerances are just too strict to have some fun, even it would be just a very minor risk for major damages.
That's why most turbo/supercharged cars have plenty of room for better ECU tune or removing of speed limiters. I tested to keep just under 3000rpm in my XJR for 10sec when the hood was up. The engine was very, very stable without any visible shaking. I do not see any differences between this and some N/A cars, why not to rev up to 6000 when tranny on P. Of course if you pump the pedal up and down, the engine starts to shake like in any other car. I can hardly believe that the AMG transmission needs a special protection.

Actually my initial question was is there any technical way to turn off that limiter. I was not asking why that should be done or not. Is it based on ECU ? My car has already an additional ECU and speed limiter has been deactivated.